Celestial Power

Galen Erso began intense research on the kyber crystals Krennic had provided him with, whilst Tarkin met with Krennic in a shipyard in Kartoosh—here, Krennic explained the potential power of the Death Star, which Tarkin regarded with mild skepticism, as well as announcing his plans to select certain worlds for the exclusive mining of resources essential to the construction of the Death Star. Tarkin found favor in Krennic's promises, and allowed Krennic to overreach his authority in order to gain the resources needed and put them tighter into Tarkin's own grasp. Krennic would use Has Obitt and other smugglers to perform smuggling operations which would require the Empire to take complete control over mining corporations—this would give Krennic the resources he needed and turn the smugglers against the Empire, which Krennic could later use to his advantage to oppose anyone who tried to circumvent his advancement of power.
With Galen in his grasp, Krennic then sprung a trap on Tarkin. Has Obitt had been angered by the destruction he had indirectly caused by following Krennic, and staged a rebellion alongside Saw Gerrera against the Imperial occupation of the Salient system and Zerpen Industries headquarters. Knowing Tarkin would not back down through fear of making the Empire look weak, he was preoccupied while Krennic was able to advance his plan without Tarkin claiming any involvement. During this battle, Galen's research advanced, and Krennic was able to get a prototype weapon created. From aboard a Star Destroyer, Krennic had the superweapon tested. The weapon was aimed at two black holes known as The Hero Twins so as to prevent any incident similar to what happened on Malpaz. At Krennic's command, the weapon was fired, and its collimating beams raced into the two black holes. It was a successful weaponizing of Galen's research, ensuring their place in history.[3] At some point during these tests, however, Krennic admitted to the Emperor that the station's primary weapon was not yet fully operational.